This invention relates generally to the field of digital data storage devices, and more particularly, but not by way of limitation, to a new system for holding discs in a multi-disc writing system.
Disc drives of the type known as xe2x80x9cWinchesterxe2x80x9d disc drives, or hard disc drives, are well known in the industry. Such disc drives magnetically record digital data on a plurality of circular, concentric data tracks on the surfaces of one or more rigid discs. The discs are typically mounted for rotation on the hub of a brushless DC spindle motor. In disc drives of the current generation, the spindle motor rotates the discs at speeds of up to 15,000 RPM or more.
Data are recorded to and retrieved from the discs by an array of aligned read/write head assemblies, or heads, which are controllably moved across disc surfaces from track to track by a common actuator assembly. Each of the read/write heads typically consists of an electromagnetic transducer carried on an air bearing slider. This slider acts in a cooperative aerodynamic relationship with a thin layer of air dragged along by the spinning discs to fly the head assembly in a closely spaced relationship to the disc surface. In order to maintain the proper flying relationship between the head assemblies and the discs, the head assemblies are attached to and supported by head suspensions or flexures, which are in turn attached to arms of a rotary actuator.
The actuator assembly used to move the heads from track to track has assumed many forms historically, with most disc drives of the current generation incorporating an actuator of the type referred to as a rotary voice coil actuator. A typical rotary voice coil actuator typically has a pivot shaft fixedly attached to the disc drive housing base member closely adjacent the outer diameter of the discs. The pivot shaft is mounted such that its central axis is normal to the plane of rotation of the discs. An actuator bearing housing or xe2x80x9cE blockxe2x80x9d is mounted to the pivot shaft by an arrangement of precision ball bearing assemblies, and supports a flat coil which is suspended in the magnetic field of an array of permanent magnets, which are fixedly mounted to the disc drive housing base member. On the side of the actuator bearing housing opposite to the coil, the actuator bearing housing also typically includes a plurality of aligned, radially extending actuator mounting arms, to which the head suspensions mentioned above are mounted. When controlled DC current is applied to the coil, a magnetic field is formed surrounding the coil which interacts with the magnetic field of the permanent magnets to rotate the actuator bearing housing or xe2x80x9cE blockxe2x80x9d, with the attached head suspensions and head assemblies. As the actuator bearing housing rotates, the heads are moved across the data tracks along an arcuate path approximating a radial movement between the disc inner and outer diameters.
Disc drives of the current generation are included in desk-top computer systems for office and home environments, as well as in laptop computers which, because of their portability, can be used wherever they can be transported. Because of this wide range of operating environments, the computer systems, as well as the disc drives incorporated in them, must be capable of reliable operation over a wide range of ambient temperatures. Furthermore, laptop computers in particular can be expected to be subjected to large amounts of mechanical shock as they are moved about. It is common in the industry, therefore, that disc drives be specified to operate over ambient temperature ranges of from, for instance, xe2x88x925 degrees Celsius to 60 degrees Celsius, and further be specified to be capable of withstanding operating mechanical shocks of 100 G or greater without becoming inoperable.
One of the areas of disc drive design which is of particular concern when considering ambient temperature variations and mechanical shock resistance is the system used to mount and clamp the discs to the spindle motor. During manufacture, the discs are typically mounted and clamped to the spindle motor in a temperature- and cleanliness-controlled environment. Once mechanical assembly of the disc drive is completed, special servo-writers are typically used to record servo information on the discs. This servo information is used during operation of the disc drive to control the positioning of the actuator used to move the read/write heads to the desired data location in a manner well known in the industry. Once the servo information has been recorded on the discs, it is assumed by the servo logic that the servo information, and all data subsequently recorded, are on circular tracks that are concentric with relation to the spin axis of the spindle motor. The discs, therefore, must be mounted and clamped to the spindle motor in a manner that prevents shifting of the discs relative to the spindle motor due to differential thermal expansion of the discs and motor components over the specified temperature range, or due to mechanical shock applied to the host computer system.
Disc stacks are also becoming used in servo writing operations where discs are written with servo data on a multiple disc writer spindle assembly and then placed onto the spindle motor. To increase throughput from such servo writing operations, the number of discs placed on a disc stack is increasing. Also, as data density on the discs increases, more precise control of the disc stack during data writing operations is desired. There is a need for a method and device to securely position the stack of discs to the spindle assembly in the servo writer. The present invention, described below, provides a solution to this and other problems, and offers other advantages over the prior art.
Against this backdrop the present invention has been developed. Embodiments of the present invention generally relate to a disc clamp arrangement including a disc clamp having an axial catch for securing an information storage disc on a spindle hub in a disc drive. The disc clamping arrangement also preferably includes retaining means for removably securing the disc clamp to the spindle hub.
Preferred embodiments of the present invention are directed to a disc clamping system for a disc stack array on a spindle hub. The disc clamping system includes a disc clamp having an axial catch and further includes a retaining arrangement for engaging the axial catch. The retaining arrangement includes at least one radially movable member that engages and secures the axial catch in an engagement position and disengages the axial catch in a disengagement position. xe2x80x9cRadially movablexe2x80x9d refers herein to any element in an assembly that has a range of motion enabling it to move closer to or farther from the array""s axis of rotation. The movement need not be precisely along a single radius.
Other preferred embodiments of the present invention are directed to a releasable, rotatable disc positioning system. The disc positioning system includes a spindle hub and a disc stack on the spindle hub and the disc stack further includes at least one disc. The disc positioning system further includes a disc clamp including an axial catch. The disc positioning system further includes a retaining arrangement for engaging the axial catch, wherein the retaining arrangement includes a plurality of radially movable members that engage and secure the axial catch in an engagement position and disengage the axial catch in a disengagement position.
Other preferred embodiments contemplate a clamping system for clamping an object to a supporting surface with a clamping force that is directed along a clamping force axis. The clamping system comprises a clamp moveable along the clamping force axis. The clamping system comprises a catch defining an abutment surface that is noncoplanar with the clamping force axis. The clamping system further comprises a retaining assembly comprising a retaining member that is moveable in a first direction transverse to the clamping force axis to engage against the abutment surface, and is moveable in a second direction along the clamping force axis to impart the clamping force against the abutment surface in a clamped position of the clamping assembly.
Other preferred embodiments contemplate a disc stack clamping assembly comprising a hub adapted to support the disc stack having one or more discs. The disc stack clamping assembly further comprises a disc clamp insertable axially in the hub, the disc clamp comprising a catch defining a nonaxial abutment surface. A retaining assembly is supported by the hub comprising a retaining member that is moveable radially to engage against the abutment surface and moveable axially to impart an axial force against the abutment surface in clamping the clamp against the disc stack.
These and various other features as well as advantages which characterize the present invention will be apparent from a reading of the following detailed description and a review of the associated drawings.